Webhook Processing Backend Needed

I need a solid back-end developer to build a small but rock-steady webhook service that can sit between several in-house apps and our selected external tools. The core job is straightforward: accept event notifications coming from multiple internal sources, confirm each request with API key validation, process the payload, then fan the data out to two targets we rely on every day—our email service and our CRM.

Key expectations
• A single endpoint (or a tidy set, if you prefer) that receives HTTPS POST requests, logs them, and rejects anything that fails API key verification.
• A processing layer that can transform or enrich the payload so it lands in the right format for both destinations.
• Reliable delivery to the email platform and the CRM, with sensible retries, idempotency, and simple monitoring hooks so we see failures quickly.
• Clean, well-documented code plus a short “getting started” README that lets another developer run the service locally, drop it into Docker, or deploy it to a cloud function with minimal fuss.

Acceptance criteria
1. Every incoming call without a valid API key is rejected with the correct HTTP status and message.
2. Valid events are delivered to both external services and logged.
3. A sample test script proves the retry logic and idempotency handling.
4. Documentation covers setup, environment variables, and a quick curl example.

Stack is up to you; I’m used to reviewing Node.js, Python (FastAPI), or Go, but if you have a better match for low-latency webhooks, pitch it. Let me know your preferred language, any open-source libraries you’d pull in, and the timeline you’ll need to hit the acceptance criteria.